1. Field of the Invention
The present invention generally relates to the field of data processing systems, and, more specifically, to methods of authenticating users of data processing systems.
2. Description of the Related Art
Nowadays, authenticating (i.e., verifying the identity of) users of data processing systems for the purpose of granting them the right of accessing predetermined services is a problem particularly felt.
For the purposes of the present description, the term service is to be construed broadly, so as to include any possible service that a data processing system can offer to a user, including simple log-in to a computer and/or to a computer network, connection to the intranet of a company, a public administration, a government agency, and/or to the Internet, access to an electronic messaging service, access to a Web site offering for example remote banking services (account inspection and/or placement of dispositions), access to databases and so on (this is merely a limited and not at all exhaustive list of what is meant by service in the context of the present description).
In particular, a secure authentication of the users that request access to specific services offered by a data processing system is important whenever these services involve making available to the users confidential information, such as for example the content of electronic messaging mailboxes, or personal information relating for example to the health of individuals, or research projects of a company, just to cite a few examples.
The problem of authenticating users is not only encountered on such a large scale data processing system as the Internet (which, despite its impressive success, is known to be extremely insecure), but also on a smaller scale, such as in data processing infrastructures of medium- or even small-size companies, where access to particular services such as employee payroll databases, accounting registers and the like are to be granted to the users on a selective basis.
Several authentication methods have been proposed. Probably the most widely adopted authentication solution relies on conditioning the access to predetermined services to the provision by the user of a personal identification code, typically a username and password pair.
This technique, also known as static password-based authentication, is extremely insecure, for example because the users, worried to forget the username and password assigned thereto, may write them down on, e.g., paper, rendering these personal identification codes, that should instead be kept strictly secret, potentially accessible to other people; additionally, the username and password normally travel through the data processing system without any encryption, and can thus get more or less fraudulently caught by other people, listening into the data traffic.
An improved authentication method is described in the U.S. Pat. No. 6,230,002 B1, relating to the authentication of wireless hosts associated with mobile GSM (Global System for Mobile communications) terminals. In this method, a password is generated by a Subscriber Identification Module (SIM) of a mobile GSM terminal coupled to the wireless host, and the generated password is communicated (via the GSM network) to an authentication server of a private network for gaining access to a protected site thereof.
Some of the authentication methods proposed more recently are derived from the realm of mobile phone communications systems, especially the GSM.
In all the methods of this class, use is made for the authentication of the SIM that every mobile phone includes and that stores information on the subscriber of the mobile phone communications service, particularly data used to permit the mobile phone gaining access to the GSM network.
This is for example the case of the authentication method and system described in the International application No. WO 00/02406, wherein a user of an Internet Protocol (IP) communications network (such as the Internet), wishing to get connected to the IP network via his/her IP network terminal (e.g., a Personal Digital Assistant—PDA), uses the same (or an essentially similar) SIM as used in his/her GSM mobile phone for authentication in the IP network, thereby the authentication method of an existing GSM network is utilized for authenticating in the IP network.
Other known authentication methods make use of a secure, SIM-authenticated communication channel formed by a GSM phone network for distributing passwords to users, which then use the passwords received on, e.g., their personal mobile phone for accessing services provided through a non-secure channel such as the Internet.
An example of this type of methods is provided in the United States Patent Application Publication US 2003/0061503 A1, describing an authentication method according to which when a non-authenticatable device corresponding to a user requests a service via an insecure link such as the Internet, or a Local Area Network (a LAN) or a Wireless LAN, during the log-in to the service the user identifies a secure link associated therewith, giving the personal mobile telephone number. The mobile phone of the user is then contacted, and a (preferably usable only once) password is communicated to him/her; by entering the password through the non-authenticatable device, the user is authorized to access the service.
The Applicant observes that the authentication methods known in the art, albeit satisfactory under many respects, do not however guarantee a sufficient level of authentication security.
In particular, in systems such as those according to the first two examples described above, the SIM that is used for authenticating the intended user of the data processing system services may get lost or be fraudulently subtracted to the legitimate owner, and unauthorized persons may thus have granted access to the restricted-exploitation services.
Something similar may happen in systems relying on the distribution of passwords through the GSM network: also in this case, the GSM terminal, or even only the SIM used for authenticating the user's GSM terminal in the GSM network may get lost or be fraudulently subtracted, thereby unauthorized persons may have granted access to the restricted-use services.